You can make yourself in English pretty well if you keep on speaking the language.A. unde

问题补充：

You can make yourself in English pretty well if you keep on speaking the language.

A. understand

B. understanding

C. to understand

D. understood

答案：

A. understand

B. understanding

C. to understand

(答案→)D. understood

解析：句意：如果反复练习这个语言，你可以很好的用英语表达自己。这里是用make+宾语+宾语补足语，因为yourself和understand是被动关系，用过去分词做宾语补足语，所以选D。